static void atomic (lua_State *L) { global_State *g = G(L); size_t udsize; /* total size of userdata to be finalized */ /* remark occasional upvalues of (maybe) dead threads */ remarkupvals(g); /* traverse objects cautch by write barrier and by 'remarkupvals' */ propagateall(g); /* remark weak tables */ g->gray = g->weak; g->weak = NULL; lua_assert(!iswhite(obj2gco(g->mainthread))); markobject(g, L); /* mark running thread */ markmt(g); /* mark basic metatables (again) */ propagateall(g); /* remark gray again */ g->gray = g->grayagain; g->grayagain = NULL; propagateall(g); udsize = luaC_separateudata(L, 0); /* separate userdata to be finalized */ marktmu(g); /* mark `preserved' userdata */ udsize += propagateall(g); /* remark, to propagate `preserveness' */ cleartable(g->weak); /* remove collected objects from weak tables */ /* flip current white */ g->currentwhite = cast_byte(otherwhite(g)); g->sweepstrgc = 0; g->sweepgc = &g->rootgc; g->gcstate = GCSsweepstring; g->estimate = g->totalbytes - udsize; /* first estimate */ }
static void atomic (lua_State *L) { global_State *g = G(L); GCObject *origweak, *origall; lua_assert(!iswhite(obj2gco(g->mainthread))); markobject(g, L); /* mark running thread */ /* registry and global metatables may be changed by API */ markvalue(g, &g->l_registry); markmt(g); /* mark basic metatables */ /* remark occasional upvalues of (maybe) dead threads */ remarkupvals(g); /* traverse objects caught by write barrier and by 'remarkupvals' */ retraversegrays(g); convergeephemerons(g); /* at this point, all strongly accessible objects are marked. */ /* clear values from weak tables, before checking finalizers */ clearvalues(g->weak, NULL); clearvalues(g->allweak, NULL); origweak = g->weak; origall = g->allweak; separatetobefnz(L, 0); /* separate objects to be finalized */ markbeingfnz(g); /* mark userdata that will be finalized */ propagateall(g); /* remark, to propagate `preserveness' */ convergeephemerons(g); /* at this point, all resurrected objects are marked. */ /* remove dead objects from weak tables */ clearkeys(g->ephemeron, NULL); /* clear keys from all ephemeron tables */ clearkeys(g->allweak, NULL); /* clear keys from all allweak tables */ /* clear values from resurrected weak tables */ clearvalues(g->weak, origweak); clearvalues(g->allweak, origall); g->sweepstrgc = 0; /* prepare to sweep strings */ g->gcstate = GCSsweepstring; g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */ /*lua_checkmemory(L);*/ }
static l_mem atomic (lua_State *L) { global_State *g = G(L); l_mem work; GCObject *origweak, *origall; GCObject *grayagain = g->grayagain; /* save original list */ lua_assert(g->ephemeron == NULL && g->weak == NULL); lua_assert(!iswhite(g->mainthread)); g->gcstate = GCSinsideatomic; g->GCmemtrav = 0; /* start counting work */ markobject(g, L); /* mark running thread */ /* registry and global metatables may be changed by API */ markvalue(g, &g->l_registry); markmt(g); /* mark global metatables */ /* remark occasional upvalues of (maybe) dead threads */ remarkupvals(g); propagateall(g); /* propagate changes */ work = g->GCmemtrav; /* stop counting (do not recount 'grayagain') */ g->gray = grayagain; propagateall(g); /* traverse 'grayagain' list */ g->GCmemtrav = 0; /* restart counting */ convergeephemerons(g); /* at this point, all strongly accessible objects are marked. */ /* Clear values from weak tables, before checking finalizers */ clearvalues(g, g->weak, NULL); clearvalues(g, g->allweak, NULL); origweak = g->weak; origall = g->allweak; work += g->GCmemtrav; /* stop counting (objects being finalized) */ separatetobefnz(g, 0); /* separate objects to be finalized */ g->gcfinnum = 1; /* there may be objects to be finalized */ markbeingfnz(g); /* mark objects that will be finalized */ propagateall(g); /* remark, to propagate 'resurrection' */ g->GCmemtrav = 0; /* restart counting */ convergeephemerons(g); /* at this point, all resurrected objects are marked. */ /* remove dead objects from weak tables */ clearkeys(g, g->ephemeron, NULL); /* clear keys from all ephemeron tables */ clearkeys(g, g->allweak, NULL); /* clear keys from all 'allweak' tables */ /* clear values from resurrected weak tables */ clearvalues(g, g->weak, origweak); clearvalues(g, g->allweak, origall); luaS_clearcache(g); g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */ work += g->GCmemtrav; /* complete counting */ return work; /* estimate of memory marked by 'atomic' */ }
static lu_mem singlestep (lua_State *L) { global_State *g = G(L); switch (g->gcstate) { case GCSpause: { g->GCmemtrav = g->strt.size * sizeof(GCObject*); restartcollection(g); g->gcstate = GCSpropagate; return g->GCmemtrav; } case GCSpropagate: { g->GCmemtrav = 0; lua_assert(g->gray); propagatemark(g); if (g->gray == NULL) /* no more gray objects? */ g->gcstate = GCSatomic; /* finish propagate phase */ return g->GCmemtrav; /* memory traversed in this step */ } case GCSatomic: { lu_mem work; int sw; propagateall(g); /* make sure gray list is empty */ work = atomic(L); /* work is what was traversed by 'atomic' */ sw = entersweep(L); g->GCestimate = gettotalbytes(g); /* first estimate */; return work + sw * GCSWEEPCOST; } case GCSswpallgc: { /* sweep "regular" objects */ return sweepstep(L, g, GCSswpfinobj, &g->finobj); } case GCSswpfinobj: { /* sweep objects with finalizers */ return sweepstep(L, g, GCSswptobefnz, &g->tobefnz); } case GCSswptobefnz: { /* sweep objects to be finalized */ return sweepstep(L, g, GCSswpend, NULL); } case GCSswpend: { /* finish sweeps */ makewhite(g, g->mainthread); /* sweep main thread */ checkSizes(L, g); g->gcstate = GCScallfin; return 0; } case GCScallfin: { /* call remaining finalizers */ if (g->tobefnz && g->gckind != KGC_EMERGENCY) { int n = runafewfinalizers(L); return (n * GCFINALIZECOST); } else { /* emergency mode or no more finalizers */ g->gcstate = GCSpause; /* finish collection */ return 0; } } default: lua_assert(0); return 0; } }
/* ** retraverse all gray lists. Because tables may be reinserted in other ** lists when traversed, traverse the original lists to avoid traversing ** twice the same table (which is not wrong, but inefficient) */ static void retraversegrays (global_State *g) { GCObject *weak = g->weak; /* save original lists */ GCObject *grayagain = g->grayagain; GCObject *ephemeron = g->ephemeron; g->weak = g->grayagain = g->ephemeron = NULL; propagateall(g); /* traverse main gray list */ propagatelist(g, grayagain); propagatelist(g, weak); propagatelist(g, ephemeron); }
static l_mem atomic (lua_State *L) { global_State *g = G(L); l_mem work = -cast(l_mem, g->GCmemtrav); /* start counting work */ GCObject *origweak, *origall; lua_assert(!iswhite(obj2gco(g->mainthread))); markobject(g, L); /* mark running thread */ /* registry and global metatables may be changed by API */ markvalue(g, &g->l_registry); markmt(g); /* mark basic metatables */ /* remark occasional upvalues of (maybe) dead threads */ remarkupvals(g); propagateall(g); /* propagate changes */ work += g->GCmemtrav; /* stop counting (do not (re)count grays) */ /* traverse objects caught by write barrier and by 'remarkupvals' */ retraversegrays(g); work -= g->GCmemtrav; /* restart counting */ convergeephemerons(g); /* at this point, all strongly accessible objects are marked. */ /* clear values from weak tables, before checking finalizers */ clearvalues(g, g->weak, NULL); clearvalues(g, g->allweak, NULL); origweak = g->weak; origall = g->allweak; work += g->GCmemtrav; /* stop counting (objects being finalized) */ separatetobefnz(L, 0); /* separate objects to be finalized */ markbeingfnz(g); /* mark objects that will be finalized */ propagateall(g); /* remark, to propagate `preserveness' */ work -= g->GCmemtrav; /* restart counting */ convergeephemerons(g); /* at this point, all resurrected objects are marked. */ /* remove dead objects from weak tables */ clearkeys(g, g->ephemeron, NULL); /* clear keys from all ephemeron tables */ clearkeys(g, g->allweak, NULL); /* clear keys from all allweak tables */ /* clear values from resurrected weak tables */ clearvalues(g, g->weak, origweak); clearvalues(g, g->allweak, origall); g->currentwhite = cast_byte(otherwhite(g)); /* flip current white */ work += g->GCmemtrav; /* complete counting */ return work; /* estimate of memory marked by 'atomic' */ }
static void convergeephemerons (global_State *g) { int changed; do { GCObject *w; GCObject *next = g->ephemeron; /* get ephemeron list */ g->ephemeron = NULL; /* tables may return to this list when traversed */ changed = 0; while ((w = next) != NULL) { next = gco2t(w)->gclist; if (traverseephemeron(g, gco2t(w))) { /* traverse marked some value? */ propagateall(g); /* propagate changes */ changed = 1; /* will have to revisit all ephemeron tables */ } } } while (changed); }
static void propagatelist (global_State *g, GCObject *l) { lua_assert(g->gray == NULL); /* no grays left */ g->gray = l; propagateall(g); /* traverse all elements from 'l' */ }